The present invention relates to the securement of windscreen wiper blade rubbers to windscreen wiper blade structures.
Conventionally windscreen wiper blade rubbers are secured to wiper blade structures by inserting the rubber into a backing strip which generally comprises a longitudinal member having a longitudinal slot to receive a head portion of wiper blade rubber. The backing strip may be a thin metal strip formed as a pair of rails joined by upraised bridge members, the rails defining a slot therebetween into which the rubber head portion is inserted. Alternatively the backing strip may be a molded or extruded plastic strip having a wiper rubber receiving slot with a narrow mouth defined by longitudinal side rails extending along the length thereof.
These backing strips serve as the means of attachment of the wiper blade rubber to the wiper blade structure. Generally the backing strip is supported between a number of longitudinally spaced, laterally opposed claws of the wiper blade structure. By this means the backing strip (with inserted rubber) is laterally secured to the wiper blade structure. However, additional means must be provided to longitudinally secure the rubber in the backing strip slot and to longitudinally secure the backing strip to the wiper blade structure.
In the prior art this longitudinal securement has been achieved in various ways.
One prior art arrangement utilizes claws at each end of the wiper blade structure which have perpendicularly protruding end pieces. The backing strip and wiper blade rubber are imprisoned between the end pieces and so are longitudinally retained. However, this arrangement is costly in that end claw members must be specifically fabricated for this purpose.
Other prior art arrangements have utilized pairs of retention clips, one attached to each of the end claws of the wiper blade. These prior art retention clips are formed with a perpendicularly extending portions which engage with the ends of the slot in the backing strip and serve to imprison the backing strip and wiper rubber therebetween. However, two clips must be used, one at end of the wiper blade.